The present invention relates to the field of television and video display and, in particular, to controlling how one video signal is superimposed over another video signal.
Many current televisions, personal video recorders (PVR), video tape recorders (VTR), media centers, and similar devices support video from many different sources. These sources may include tuners, recorders, players and cameras.
The number and types of video sources in any particular device may vary greatly. Signals from terrestrial radio broadcast, cable broadcast, satellite, optic fiber and wide area networks can all offer different programming. Players can provide video from tape, disk or memory and cameras vary greatly in capabilities. All of these sources are currently available to provide video in different formats. These include analog and digital signals with different aspect ratios, different modulation and encoding systems, different resolutions and different supporting audio formats, quality levels and numbers of channels.
In order to view or monitor all of the many different available sources of video programming, many televisions, personal video recorders (PVR), video tape recorders (VTR), media centers, and similar equipment can display one or more video programs on the same screen at the same time. Typically this is called a picture in picture (PIP) display. A PIP display is normally provided by providing a secondary video source in a smaller window superimposed over or overlaid on the primary video source. The primary video source fills the entire display area or at least the entire width or height of the display area. A typical PIP display shows the small window in the same location and same shape at all times and the user can select only which video sources or channels are to be displayed in the primary and secondary positions. In some more complex televisions more than two video sources can be displayed at the same time.